minkowski() {
    difference(){
cube([13.5+4,34,7+2],center=true);
translate([0,2,0]){
    cube([13.5,34,7],center=true);
    translate([0,-18.5,0]){
        cube([4,4,2],center=true);
    }
}
}
  cylinder(r=0.1, center=false);
}


render();